I have always had Rhino liner for my trucks. I love it. My current truck has had it in for over 15 years and it is still like new - work truck too.
​I always get the tailgate done and over the lip on the bed.

​2 things on my old truck:
​1) Had a heavy object dropped on the lip one time. It dented the lip a little. Rhino still looks new in that location, it has never cracked or lifted there over the years.
​2) Another time I had a tire blow out that smashed the wheel well up about 2-3 inches. Rhino still looks new in that location as well - no cracking, splitting, or lifting.

​I must say I don't like Line-X (unless they have changed the formula in the last 10 years). It is durable but it is rough, like sandpaper. The Rhino liner is more rubbery and fells better crawling around on it, unlike the Line-X which hurts to crawl around on it.
Don't know about Line-X and things sliding but with Rhino, nothing slides.
​I have also seen people's truck with Line-X that had the bed damaged (like I described above on my truck) and the Line-X cracked or chipped.